Yea upgrading for every single release is not necessary, Besides 3.0.1 has it's own issues with it so waiting for 3.0.2 before upgrading will be better. And the site design will be changing as well, There is already a design chosen for the site.

Is there a way to enable the "(Mark this forum as read)" feature for sub forums?

For example, when I browse the announcements board, I can click this link in the upper right corner and all the posts under anouncements will be marked as being read. But if I go up one level to the "General" subforums, there is no such link, only the "Mark Board As Read" link at the bottom of the page. This one however won't only mark the posts in the current subforums as being read, but all new posts. Marking subforums as being read would be especially usefull for the "Yii International" subforums to me, as I can't understand most of the posts there...

Not exactly what I'm looking for. I searched for a link/button that marks a whole sub forum like "Yii International" as beeing read. These blue buttons only mark single boards (Bulgarian, Chinese, ...) as beeing read. And I wondered if there might be such a feature, maybe deactivated in the admin panel.

But nontheless: better to click these blue buttons than entering the Bulgarian board, clicking "Mark as read", go back, enter the Chinese board, clicking "Mark as read", and so on. So thanks for the hint, I really didn't see those buttons.

//EDIT:
Just tried it and noticed these buttons don't cause a reload. Really nice!

Unfortunately it seems like in some posts content was lost during migration. E.g. in this post (german) the code snippets and links are gone. Can these be recovered? Some new users are complaining already...

What about this global upload limit? I attached two screenshots to the thread "[EXTENSION] srbac...". They use up one fith of my global quota. Are we suggested to delete our attachements from time to time? Or can this limit be raised/ disabled?

Well done (I appreciate your work and really like it because forum looks great now and more handy), but...
what is wrong with all links? Almost all links at tthe forum are broken now. Or only I have such issue? I am just noticing, because I think it's a number one problem at present (sorry if anybody has already pointed on this, but i didn't see it in this thread).

If I try to follow a profile or discussion page from the docs/extensions, to the forum, the URLs are no longer working, but I believe this was working previously.

And actually, just now I revisited several of the pages that were tossing bad links, and they're redirecting properly...

I think this is a session issue with the forum possibly, not sure though. The urls (just a few minutes ago) were not SEO friendly, whereas now they are being produced SEO friendly directly on the page (meaning it's not actually a redirect issue, it's an issue with how URLs are generated on the website to link to the forums).

What could be causing this?

As mentioned, the link issue is not constant, it seems to depend on my forum session being refreshed when I'm viewing the docs, as once I went to the forums to report the issue, the links were then formatted properly (w/ SEO urls) after that point.